1. Field of the Invention
The present invention relates in general to a system and method for producing a reactive force on an aerospace vehicle to cause rotation or vibration of dipoles of neutral particles having a selected electrical dipole characteristic and more particularly to a dipolar force field propulsion system for an aerospace vehicle utilizing a crossed electric E field and a magnetic B field for establishing a spatial force field region wherein a control means establishes a predetermined spatial and time relationship between the alternating electric field, alternating magnetic field and dipole rotation for a selected frequency to produce a reactive thrust.
2. Description of the Prior Art
In spacecraft propulsion systems, the use of chemical rocket engines which use combustion of chemical fuels to produce a large amount of thrust necessary to lift loads from the earth's surface is known. The term "thrust" is defined to mean the amount of propulsive force developed by a propulsion engine and is typically related to a rocket engine that is used for boosting a space vehicle from the earth's surface into orbit. The known space propulsion systems must have sufficient thrust to raise the spacecraft from the earth's surface and that thrust must be greater than the weight of the vehicle to be lifted from the earth's surface and placed into orbit.
Once the spacecraft has been boosted into space or orbit, the required spacecraft thrust is minimal compared to the thrust required for lifting the vehicles from the earth's surface.
When a spacecraft is in space or in orbit, it is desirable to have the ratio of thrust produced to the rate of consumption of the fuel to be high as possible and this is generally referred to as "specific impulse." In space or in orbit, a spacecraft propulsion system having a high "specific impulse" capability is highly desirable.
Thus, it is known in the art of space propulsion systems that the chemical rocket engines are capable of providing the requisite thrust necessary to lift large payloads from the earth's surface into orbit.
Once the spacecraft and its payload is in orbit, it is desirable for the spacecraft propulsion system to be able to change the orbit, speed and/or orbital position of the spacecraft with a "specific impulse" propulsive force.
A number of propulsion systems having the capacility of providing "specific impulse" thrust for changing the orbit, speed and/or orbital position of a spacecraft.
One such known propulsion engine is generally referred to as "electrostatic propulsion systems" wherein the thrust is created by electrostatic acceleration of ions created by an electron source in an electric field. Electrostatic propulsion systems have very high specific impulse but have limited thrust capabilities. Where an excessively large amount of thrust is required, the size and weight of the electrostatic propulsion systems become excessive. Examples of known electrostatic propulsion systems are disclosed in U.S. Pat. No. 3,866,414; U.S. Pat. No. 3,537,266 and U.S. Pat. No. 3,095,163. Electrostatic propulsion systems include electrostatic engines such as ion engines as evidenced by the above-described U.S. patents.
Another type of known space propulsion systems are generally referred to as "electric arc" engines. Electric arc engines or propulsion systems use an electric arc to heat a propulsion gas which is then passed to a standard rocket nozzle to provide thrust. Electric arc propulsion systems are capable of generating considerable amounts of thrust and have specific impulse thrust greater than those of chemical engines. However, the specific impulse thrust levels of electric arc engines are lower than the specific impulse thrust of electrostatic propulsion systems. Typical electrothermal or electric arc propulsion systems are disclosed in a book by Robert Jahn entitled "Physics of Electric Propulsion", McGraw Hill, 1968.
Another known type of spacecraft propulsion system is generally referred to as electromagnetic propulsion systems which includes magnetohydrodynamic (MHD) thruster or magnetoplasmadynamic (MPD) thruster. The MHD or MPD thrusters are capable of providing both high thrust density and high specific impulse. The MHD or MPD thrusters utilize a propellant gas which is ionized to form a plasma which is accelerated by magnetic and electric fields and is then passed through an expansion nozzle to provide thrust. In MHD thruster or MPD thruster, the plasma is a body of gas which comprises a substantial number of free electrons and ions, but has an overall neutral electrical charge providing a plasma which is electrically conductive. The known MHD or MPD thrusters utilize the interaction of magnetic fields produced by electrical currents and conductors on the spacecraft with an electrically conductive environment to produce a reaction thrust. Several typical MHD thrusters or MPD thrusters are disclosed in U.S. Pat. No. 3,735,591; U.S. Pat. No. 3,662,554; U.S. Pat. No. 3,535,586; U.S. Pat. No. 3,505,550; U.S. Pat. No. 3,371,490; U.S. Pat. No. 3,527,055; U.S. Pat. No. 3,343,022 and U.S. Pat. No. 3,322,374.
It is also known in the art to combine a jet propulsion power plant with a magnetoplasmadynamic generator to produce a hybrid propulsion system. One such propulsion system is disclosed in U.S. Pat. No. 3,678,306.
The use of a controlled fusion device which generates electrical energy utilizing an ionized gas plasma in a space propulsion system is disclosed in U.S. Pat. No. 3,324,316.
The design of plasma propulsion systems having special magnetic fields for controlling the specific impulse characteristics of the plasma propulsion device is disclosed in U.S. Pat. No. 3,191,092.
In addition to the above described space propulsion systems, the inventor of the present application published an article entitled "Electromagnetic Propulsion Without Ionization" which appeared in the AIAA/SAE/ASME 16th Joint Propulsion Conference which was held on June 13, 1980 to July 2, 1980 in Hartford, Conn. The paper presented at the above-described 16th Joint Propulsion Conference disclosed the concept of electromagnetic propulsion without ionization. Specifically, the paper disclosed that when an alternating electric field is applied to a polarized or polarizable material, the dipole of the material can be made to rotate at high frequency. If an alternating and synchronized magnetic field is supplied at right angles to the electric field, a Lorentz force is generated which propels the dielectric fluid without the necessity for ionization and the consequential energy losses arising from the ionization process. The thrust so generated is proportional to the polarization, the frequency of the dipole rotation and the magnetic field strength. The propellant selected for use as the polarizable material is characterized by having a high permanent molecular dipole movement-to-mass ratio and is accelerated by Lorentz forces to useful exit velocities. A spacecraft having the induced dipole electromagnetic propulsion system is accelerated by Newton's Third Law of Motion, or the reactive thrust principal.